Research impact: neither quick nor easy.

Greenhalgh and Fahy's paper about the 2014 Research Excellence Framework provides insights into the challenges of assessing research impact. Future research assessment exercises should consider how best to include measurement of indirect and non-linear impact and whether efforts in knowledge transfer and co-production should be explicitly recognised. Greenhalgh and Fahy's findings also demonstrate that the structure of the assessment exercise can privilege certain kinds of research and may therefore miss some research that has a high impact on policy and practice. There are a growing number of courses, tools, and funding models to assist researchers in making an impact, although as yet there is little evidence about whether these approaches work in practice. Please see related article: http://www.biomedcentral.com/1741-7015/13/232.